應用小波函數修正人造基底振動

In accordance with the seismic design procedures and criteria for offshore structures in ISO 19901-2, a nonlinear time history analysis corresponding to abnormal level earthquake is required for offshore structures at Taiwan Strait when the L1 exposure level is applicable. This article uses a linear combination of several Gauss wavelets as a base function to adjust the spectral response displacement with the maximum relative error to a target response spectrum. Through iterative operation an artificial base accelerogram compatible with the target response spectrum is then generated for use in the time history analysis of structures. Two real examples were demonstrated here. It was shown that the results using our method satisfy the requirement of 10% compatible accuracy despite the shapes of target response spectra, smooth or piecewise continuous. Furthermore, the wave forms of artificial base accelerograms were much similar to ground acceleration records, and no baseline shifts to the artificial base acceleration, velocity, and displacement time histories were observed.